As much as it is fun to speculate, I think the evidence their Silent Hills: Death Stranding theory is tenuous at best.

PythonSelkan's SHDS Theory

Is it possible to have multiple strings of coincidences and be just that? Coincidences?

Yes, absolutely.

Also, confirmation bias would also play a big role.

Besides, Kojima said outright DS is not horror and he will never make another horror game.

But it's all part of a ruse? No. Until hard evidence points to the contrary, I will take Kojima's words at face value. I will also take the news of the Kojima/Konami split at face value, not simply because of the lack of evidence, for the alternate possibility defies reason.

Do I normally trust the news and the BS the media ("mainstream" or not) happens to spew from its ungodly maw? Hell no, but I think when the news is confirmed, it makes sense to trust that tangent of news, at the very least.

I never watched the whole thing, but indeed it is incredible reaching to conclude that there is still some relationship between Konami and Kojima and that this was all planned.

Some things we can reasonably conclude though...

Kojima knew that Konami was getting rid of the KojiPro brand when he was releasing Ground Zeroes, which was likely something he was forced to do.

Kojima probably knew that he was going to break up with Konami at some near point in the future as well, so thus this explains the messages in Ground Zeroes/MGSV.

There could be some ideas Kojima had that were for Silent Hills that made it into Death Stranding. Ideas that were vague and wouldn't have Konami coming after him claiming it was their intellectual property etc. But no one can really say and that's the point.

Kojima distancing himself from horror is likely for the same above reason. Not that he'll never do a horror game with Del Toro in the future, but that it's necessary to put some distance between the Konami break up and Silent Hills.